Display device and electronic apparatus

ABSTRACT

A display device including: a plurality of sub-pixels arranged in a matrix, each including an electro-optical element having a structure in which a display functional layer is sandwiched between an upper electrode and a lower electrode; and an auxiliary interconnect contact in a pixel area in which the plurality of sub-pixels are arranged in a matrix and electrically connecting the upper electrode to an auxiliary interconnect, wherein m (m is an integer equal to or larger than two) sub-pixels adjacent to each other along an arrangement direction of the sub-pixels are regarded as one group, and n (n is a natural number smaller than m) auxiliary interconnect contacts are formed for each group.

RELATED APPLICATION DATA

This application is a continuation of U.S. patent application Ser. No.17/342,217 filed Jun. 8, 2021, which is a continuation of U.S. patentapplication Ser. No. 16/271,415 filed Feb. 8, 2019, now U.S. Pat. No.11,056,052 issued Jul. 6, 2021, which is a continuation of U.S. patentapplication Ser. No. 14/246,524 filed Apr. 7, 2014, now U.S. Pat. No.10,242,614 issued Mar. 26, 2019, which is a continuation of U.S. patentapplication Ser. No. 13/424,842, filed Mar. 20, 2012, now abandoned,which is a continuation of U.S. patent application Ser. No. 12/255,265,filed Oct. 21, 2008, now U.S. Pat. No. 8,179,339 issued on May 15, 2012,all which are incorporated herein by reference in their entireties tothe extent permitted by law. This application claims the benefit ofpriority to Japanese Patent Application No. 2007-274752 filed in theJapan Patent Office on Oct. 23, 2007, the entirely of which isincorporated herein by reference to the extent permitted by law.

BACKGROUND OF THE INVENTION

The present invention relates to a display device and an electronicapparatus, and particularly to a flat-type (flat-panel-type) displaydevice in which pixels each including an electro-optical element arearranged on rows and columns (in a matrix), and an electronic apparatushaving the display device.

In recent years, in the field of display devices for image displaying,flat-type display devices in which pixels each including a lightemitting element are arranged in a matrix are rapidly becomingwidespread. As one of the flat-type display devices, e.g. an organicelectro luminescence (EL) display device is developed andcommercialization thereof is being advanced. The organic EL displaydevice includes organic EL elements as the light emitting elements ofthe respective pixels. The organic EL element is a so-calledcurrent-driven electro-optical element whose light emission luminancevaries depending on the value of the current that flows through theelement, and is based on a phenomenon that light emission occurs inresponse to electric field application to an organic thin film.

The organic EL display device has the following features. Specifically,the organic EL display device has low power consumption because theorganic EL element can be driven by application voltage equal to orlower than 10 V. Furthermore, the organic EL element is a self-luminouselement. Therefore, the organic EL display device provides higher imagevisibility compared with a liquid crystal display device, which displaysan image by controlling, for each pixel including a liquid crystal cell,the intensity of light from a light source (backlight) by using theliquid crystal cell. In addition, the organic EL display device does notneed to have an illuminating unit such as a backlight, which isnecessary for the liquid crystal display device, and thus is allowed toeasily achieve reduced weight and thickness. Moreover, the responsespeed of the organic EL element is as very high as several microseconds,which causes no image lag in displaying of a moving image by the organicEL display device.

As the drive system for the organic EL display device, a simple-(passive-) matrix system or an active-matrix system can be employed,similarly to the liquid crystal display device. However, a displaydevice of the simple-matrix system involves e.g. a problem that it isdifficult to realize a large-size and high-definition display devicebecause the light emission period of the electro-optical element becomesshorter as the number of scan lines increases, although the structure ofthe simple-matrix display device is simple.

Therefore, currently, a display device of the active-matrix systempredominates, in which the current that flows through an electro-opticalelement is controlled by an active element, such as an insulated gatefield effect transistor (typically, thin film transistor (TFT)),provided in a pixel circuit corresponding to this electro-opticalelement. In the display device of the active-matrix system, theelectro-optical element continues light emission over the one-frameperiod. This easily realizes a display device having large size and highdefinition.

In general, the organic EL element used in the organic EL display devicehas a structure in which an organic layer composed of an organicmaterial is interposed between a cathode electrode and an anodeelectrode in a sandwiched manner. For the light emission of the organicEL element, positive voltage is applied to the anode electrode andnegative electrode is applied to the cathode electrode. Due to thisvoltage application, holes are injected into the organic layer from theanode electrode side and electrons are injected from the cathodeelectrode side. These holes and electrons recombine with each otherinside the organic layer (light emitting layer), which causes the lightemission.

The pixels as the minimum unit of image displaying by the organic ELdisplay device (hereinafter, referred to as the “sub-pixels”) are soprovided as to be separated for each of colors of red (R), green (G),and blue (B) as three primary colors of light. Each sub-pixel includesan organic EL element as an electro-optical element and a pixel contactfor electrically connecting this organic EL element to a pixel circuit.The pixel circuit is a circuit to control the current that flows throughthe electro-optical element (organic EL element). Typically, the pixelcircuit and the sub-pixel are provided with the one-to-onecorrespondence relationship.

It is effective that an active-matrix display device has a so-calledtop-face light extraction structure (hereinafter, referred to as the“top-emission structure”) for extracting light from the opposite side toa transparent insulating substrate on which the pixel circuits areformed, in order to assure a high aperture ratio of the organic ELelement. In the organic EL display device of the top-emission structure,an upper electrode that sandwiches the organic layer together with alower electrode is formed of e.g. a very thin metal film in order toassure high optical transmittance. Therefore, the sheet resistance ofthe upper electrode is high, and thus a voltage drop easily occurs whenvoltage is applied to the upper electrode.

To address this problem, a structure to prevent a voltage drop in theupper electrode has been proposed as a related art. In this structure,an auxiliary interconnect is formed at the same layer level as that ofthe lower electrode by using a low-resistance metal material (e.g.silver, aluminum), and the upper electrode is electrically connected tothis auxiliary interconnect via an auxiliary interconnect contact (referto e.g. Japanese Patent Laid-open No. 2004-207217).

SUMMARY OF THE INVENTION

FIG. 24 is a schematic plan view showing the layout in an organic ELdisplay device of a top-emission structure. For a substrate 51 forforming organic EL elements (hereinafter, referred to as the “elementformation substrate”), a transparent glass substrate is used as atransparent insulating substrate. An auxiliary electrode 52 is formedinto a rectangular frame shape on the element formation substrate 51.Plural sub-pixels 53 are arranged in a matrix in the area surrounded bythe auxiliary electrode 52 (hereinafter, referred to as the “pixelarea”). In each sub-pixel 53, a pixel contact 54 is provided.

The pixel contact 54 is provided to electrically connect, of the cathodeelectrode and the anode electrode that sandwich the organic layer asdescribed above, a pixel electrode formed for each sub-pixel 53separately to the pixel circuit (not shown). The pixel electrodesandwiches the organic layer together with a common electrode opposed tothe pixel electrode. The common electrode is formed as a blanketelectrode layer common to all of the sub-pixels 53. When the elementformation substrate 51 is horizontally disposed, the pixel electrode andthe common electrode serve as the lower electrode and the upperelectrode, respectively, and the upper electrode side corresponds to thelight extraction side.

In the pixel area surrounded by the auxiliary electrode 52, auxiliaryinterconnects 55 are so formed vertically and horizontally as to extendamong the respective sub-pixels 53. The auxiliary interconnects 55 areformed together with the auxiliary electrode 52 at the same layer levelas that of the pixel electrodes (not shown). The above-described upperelectrode (common electrode) is electrically connected to the auxiliaryelectrode 52 via plural auxiliary electrode contacts 56. Furthermore,the upper electrode is electrically connected to the auxiliaryinterconnects 55 via plural auxiliary interconnect contacts 57.

However, in this organic EL display device, the auxiliary interconnectcontacts 57 exist between the respective two of all of the sub-pixels 53adjacent to each other along the row direction (vertical direction).Therefore, in accordance with the rule of the manufacturing process andthe design rule, the area for forming the auxiliary interconnects 55 andthe auxiliary interconnect contacts 57 needs to be ensured between therespective two of all of the sub-pixels 53 adjacent to each other alongthe row direction. This results in the state in which the sub-pixels arearranged with low density in the pixel area.

According to an embodiment of the present invention, there is provided adisplay device including a plurality of sub-pixels configured to bearranged in a matrix and each include an electro-optical element havinga structure in which a display functional layer is sandwiched between anupper electrode and a lower electrode, and an auxiliary interconnectcontact configured to be formed in a pixel area in which the pluralityof sub-pixels are arranged in a matrix and electrically connect theupper electrode to an auxiliary interconnect. In the display device, m(m is an integer equal to or larger than two) sub-pixels adjacent toeach other along an arrangement direction of the sub-pixels are regardedas one group, and n (n is a natural number smaller than m) auxiliaryinterconnect contacts are formed for each group.

In the display device according to the embodiment of the presentinvention and an electronic apparatus having the display device, msub-pixels adjacent to each other along an arrangement direction of thesub-pixels are regarded as one group, and n auxiliary interconnectcontacts are formed for each group. This makes it possible to arrangethe sub-pixels with smaller pixel distance and hence higher densityalong the arrangement direction thereof, compared with related arts.

According to the embodiment of the present invention, in a displaydevice in which an upper electrode is electrically connected to anauxiliary interconnect to thereby decrease the resistance of the upperelectrode, sub-pixels can be arranged with smaller pixel distance andhence higher density along the arrangement direction thereof, comparedwith related arts. Thus, enhancement in the aperture ratio of the pixelsand the definition of displaying can be realized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view showing the configuration of major part of adisplay device to which an embodiment of the present invention isapplied;

FIG. 2 is a sectional view showing one example of the multilayerstructure of organic EL elements;

FIG. 3 is a diagram showing a configuration example of a drive circuitin the organic EL display device;

FIG. 4 is a diagram showing a configuration example of a pixel circuit;

FIG. 5 is a schematic plan view showing the layout in an organic ELdisplay device according to a first embodiment of the present invention;

FIG. 6 is a sectional view of major part of the organic EL displaydevice of the first embodiment of the present invention;

FIG. 7 is a schematic plan view showing the layout in an organic ELdisplay device according to a second embodiment of the presentinvention;

FIG. 8 is a schematic diagram showing one example of the colorarrangement of pixels;

FIG. 9 is a schematic plan view showing the layout in an organic ELdisplay device according to a third embodiment of the present invention;

FIG. 10 is a schematic plan view showing the layout in an organic ELdisplay device according to a fourth embodiment of the presentinvention;

FIG. 11 is a schematic plan view showing the layout in an organic ELdisplay device according to a fifth embodiment of the present invention;

FIG. 12 is a schematic plan view showing the layout in an organic ELdisplay device according to a sixth embodiment of the present invention;

FIG. 13 is a schematic plan view showing the layout in an organic ELdisplay device according to a seventh embodiment of the presentinvention;

FIG. 14 is a schematic plan view showing the layout in an organic ELdisplay device according to an eighth embodiment of the presentinvention;

FIG. 15 is a schematic plan view showing the layout in an organic ELdisplay device according to a ninth embodiment of the present invention.

FIG. 16 is a schematic plan view showing the layout in an organic ELdisplay device according to a tenth embodiment of the present invention;

FIG. 17 is a schematic plan view showing the layout in an organic ELdisplay device according to an eleventh embodiment of the presentinvention;

FIG. 18 is a sectional view of major part of the organic EL displaydevice of the eleventh embodiment of the present invention;

FIG. 19 is a perspective view showing a television as a firstapplication example;

FIGS. 20A and 20B are diagrams showing a digital camera as a secondapplication example;

FIG. 21 is a perspective view showing a laptop personal computer as athird application example;

FIG. 22 is a perspective view showing a video camera as a fourthapplication example;

FIGS. 23A to 23G are diagrams showing a portable terminal apparatus as afifth application example; and

FIG. 24 is a schematic plan view showing the layout in an organic ELdisplay device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will be described in detail belowwith reference to the accompanying drawings.

<Configuration of Display Device>

FIG. 1 is a sectional view showing the configuration of major part of adisplay device to which an embodiment of the present invention isapplied. As one example, the following description will deal with anactive-matrix organic EL display device that employs, as a lightemitting element of each pixel, an organic EL element (organic electroluminescence element), which is a current-driven electro-optical elementwhose light emission luminance varies depending on the current thatflows through the element.

An organic EL display device 1 is formed by using plural (a large numberof) organic EL elements 2. The organic EL elements 2 are separated foreach sub-pixel based on the difference of the light emission color amongred (R), green (G), and blue (B). FIG. 1 shows only one of these organicEL elements 2.

The organic EL element 2 is formed by using an element formationsubstrate 3. Over the element formation substrate 3, in addition to apixel circuit (not shown) including an active element (e.g. thin filmtransistor), a lower electrode 4, an insulating layer 5, an organiclayer 6, and an upper electrode 7 are sequentially stacked. The upperelectrode 7 is covered by a protective layer 8, and a counter substrate10 is disposed over this protective layer 8 with the intermediary of anadhesive layer 9 therebetween. The organic EL element 2 has a structurein which the organic layer 6 composed of an organic material isinterposed between the lower electrode 4 and the upper electrode 7 in asandwiched manner.

Each of the element formation substrate 3 and the counter substrate 10is formed of a transparent glass substrate (insulating substrate). Theelement formation substrate 3 and the counter substrate 10 are disposedto face each other in such a way that the lower electrode 4, theinsulating layer 5, the organic layer 6, the upper electrode 7, theprotective layer 8, and the adhesive layer 9 are sandwiched betweenthese two substrates.

One of the lower electrode 4 and the upper electrode 7 serves as theanode electrode, and the other serves as the cathode electrode. Thelower electrode 4 is composed of a highly-reflective material if theorganic EL display device 1 is a top-emission display device, and it iscomposed of a transparent material if the organic EL display device 1 isa transmissive display device.

The structure of FIG. 1 is based on an assumption that the organic ELdisplay device 1 is a top-emission display device and the lowerelectrode 4 and the upper electrode 7 serve as the anode electrode andthe cathode electrode, respectively, as one example. In this case, thelower electrode 4 is formed for each sub-pixel separately, and thus isequivalent to the pixel electrode. In contrast, the upper electrode 7serves as the common electrode that is common to all of the sub-pixels.Thus, the upper electrode 7 is formed into a blanket film state acrossthe entire surface of the element formation substrate 3 in such a manneras to cover the organic layer 6. The lower electrode 4 is composed ofany of the following electrically-conductive materials with highreflectivity and alloys of these materials: silver (Ag), aluminum (Al),chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu),tantalum (Ta), tungsten (W), platinum (Pt), and gold (Au).

If the organic EL display device 1 is a top-emission display device andthe lower electrode 4 is the cathode electrode, the lower electrode 4 iscomposed of an electrically-conductive material having a low workfunction and high optical reflectivity, such as aluminum (Al), indium(In), magnesium (Mg)-silver (Ag) alloy, lithium (Li)-fluorine (F)compound, lithium-oxygen (O) compound.

If the organic EL display device 1 is a transmissive display device andthe lower electrode 4 is the anode electrode, the lower electrode 4 iscomposed of an electrically-conductive material having hightransmittance, such as indium tin oxide (ITO) or indium zinc oxide(IZO). If the organic EL display device 1 is a transmissive displaydevice and the lower electrode 4 is the cathode electrode, the lowerelectrode 4 is composed of an electrically-conductive material having alow work function and high optical transmittance.

The insulating layer 5 is formed on the top surface of the elementformation substrate 3 in such a manner as to cover the peripheral partof the lower electrode 4. A window is formed in the insulating layer 5for each sub-pixel, and the lower electrode 4 is exposed through theaperture part of this window. This insulating layer 5 is formed by usinge.g. an organic insulating material such as polyimide or photoresist, oran inorganic insulating material such as silicon oxide.

The organic layer 6 is formed as a display functional layer between thelower electrode 4 and the upper electrode 7. As shown in FIG. 2 , theorganic layer 6 has e.g. a four-layer multilayer structure arising fromstacking of a hole injection layer 61, a hole transport layer 62, alight emitting layer 63 (63 r, 63 g, 63 b), and an electron transportlayer 64 in that order from the element formation substrate 3 side.

The hole injection layer 61 is composed of e.g. m-MTDATA[4,4,4-tris(3-methylphenylphenylamino)triphenylamine]. The holetransport layer 62 is composed of e.g. α-NPD[4,4-bis(N-1-naphthyl-N-phenylamino)biphenyl]. The material is notlimited thereto, but another hole transport material such as a benzidinederivative, styrylamine derivative, triphenylmethane derivative, orhydrazone derivative can be used. Each of the hole injection layer 61and the hole transport layer 62 may have a multilayer structure composedof plural layers.

The light emitting layers 63 are composed of organic light emittingmaterials different for each of the RGB color components. Specifically,the red light emitting layer 63 r is composed of e.g. a materialprepared by doping ADN as a host material with 30-wt. %2,6≡bis[(4′≡methoxydiphenylamino)styryl]≡1,5≡dicyanonaphthalene (BSN) asa dopant material. The green light emitting layer 63 g is composed ofe.g. a material prepared by doping ADN as a host material with 5-wt. %coumarin 6 as a dopant material. The blue light emitting layer 63 b iscomposed of e.g. a material prepared by doping ADN as a host materialwith 2.5-wt. % 4,4′≡bis[2≡{4≡(N,N≡diphenylamino)phenyl}vinyl]biphenyl(DPAVBi) as a dopant material. In matching with the color arrangement ofthe pixels, the light emitting layers 63 r, 63 g, and 63 b of therespective colors are arranged in a matrix similar to that of thesub-pixels, or arranged as strips parallel to the row direction of thesub-pixels.

The electron transport layer 64 is composed of e.g. 8≡hydroxyquinolinealuminum (Alq3). The structure of the organic layer 6 is not limited tothe four-layer structure shown in FIG. 2 , but any structure may beemployed as long as the organic layer 6 includes at least the lightemitting layer. Specifically, the organic layer 6 may have a five-layerstructure obtained by adding an electron injection layer (not shown) tothe above-described four layers (hole injection layer, hole transportlayer, light emitting layers, electron transport layer). Alternatively,it may have a structure with a smaller or larger number of layers.

The upper electrode 7 is composed of a transparent or semi-transparentelectrically-conductive material, such as a very thin metal film, ITO,or IZO, if the organic EL display device 1 is a top-emission displaydevice, and it is composed of a highly-reflective material if theorganic EL display device 1 is a transmissive display device. Inparticular, if the organic EL display device 1 is a top-emission displaydevice, the upper electrode 7, which is on the light extraction side,needs to have both optical transparency and electrical conductivity.Therefore, the electric resistance (sheet resistance) of the upperelectrode 7 is higher than that of the lower electrode 4, which isformed by using a low-resistance material such as aluminum or silver.

Based on the lower electrode 4, the insulating layer 5, the organiclayer 6, and the upper electrode 7 thus formed over the elementformation substrate 3, the organic EL element 2 (red organic EL element2 r, green organic EL element 2 g, blue organic EL element 2 b) isformed.

The protective layer 8 is formed for the purpose of preventing waterfrom reaching the upper electrode 7 and the organic layer 6 and otherpurposes. Thus, the protective layer 8 is formed to a sufficientthickness by using a material with low water permeability and low waterabsorbability. If the organic EL display device 1 is a top-emissiondisplay device, the protective layer 8 needs to allow the passage oflight emitted by the organic layer 6 therethrough, and therefore iscomposed of a material having optical transparency of about 80%.

If the upper electrode 7 is formed of a metal thin film and theinsulating protective layer 8 is formed directly on this metal thinfilm, as the material of the protective layer 8, an inorganic amorphousinsulating material such as amorphous silicon (α-Si), amorphous siliconcarbide (α-SiC), amorphous silicon nitride (α-Si1−xNx), or amorphouscarbon (α-C) can be favorably used. Such an inorganic amorphousinsulating material includes no grain and thus has low waterpermeability, and hence provides the favorable protective film 8.

The adhesive layer 9 is composed of e.g. UV (ultra-violet rays) curingresin. The adhesive layer 9 is to fix the counter substrate 10.

Although not shown in the drawing, in the case of combining a colorfilter with the organic EL display device 1 having such a configuration,color filters that each allow the passage of only light around the peakwavelength of the spectrum of light emission by a corresponding one ofthe organic EL elements 2 r, 2 g, and 2 b of the respective RGB colorsare provided on the light extraction surface side of the organic ELelements 2 r, 2 g, and 2 b of the respective colors.

<Configuration of Drive Circuit>

FIG. 3 is a diagram showing a configuration example of a drive circuitin the organic EL display device. The drive circuit of the organic ELdisplay device 1 is formed over the element formation substrate 3. Morespecifically, a display area 11 including the pixel area and aperipheral area 12 thereof are defined on the element formationsubstrate 3. In the display area 11, plural scan lines 13 and pluralsignal lines 14 are disposed horizontally and vertically. One sub-pixel15 is provided at each of the intersections of the scan lines 13 and thesignal lines 14. The plural (a large number of) sub-pixels 15 arearranged in a matrix in the display area 11. The arrangement directionsof the sub-pixels 15 on the element formation substrate 3 are the rowdirection equivalent to the vertical direction on the display screen(the upward and downward directions in the drawing) and the columndirection equivalent to the horizontal direction on the display screen(the leftward and rightward directions in the drawing). Each of thesub-pixels 15 includes the above-described organic EL element 2.Disposed in the peripheral area 12 are a scan line drive circuit 16 forscan-driving of the scan lines 13 and a signal line drive circuit 17that supplies video signals (i.e. input signals) dependent uponluminance information to the signal lines 14.

<Configuration of Pixel Circuit>

FIG. 4 is a diagram showing a configuration example of the pixelcircuit. This pixel circuit 18 is a circuit to control the current thatflows through the organic EL element 2. In FIG. 4 , the pixel circuit 18corresponding to one sub-pixel is formed by using a drive transistorTr1, a write transistor Tr2, and a hold capacitor Cs, as one example. Inthis pixel circuit 18, due to driving by the scan line drive circuit 16,a video signal written from the signal line 14 via the write transistorTr2 is held in the hold capacitor Cs, and the current dependent upon theamount of the held signal is supplied from the drive transistor Tr1 tothe organic EL element 2, so that the organic EL element 2 emits lightwith the luminance dependent upon the current value.

This pixel circuit configuration is merely one example, and the pixelcircuit may further include an additional capacitive element and pluraltransistors according to need. Furthermore, a requisite drive circuitmay be added to the peripheral area 12 depending on the change of thepixel circuit.

First Embodiment

FIG. 5 is a schematic plan view showing the layout in an organic ELdisplay device according to a first embodiment of the present invention.FIG. 6 is a sectional view of major part of the organic EL displaydevice of the first embodiment.

The pixel circuit 18 is formed on the element formation substrate 3together with the organic EL element 2. For example, the pixel circuit18 is formed on the element formation substrate 3 by usingpublicly-known thin film forming technique, patterning technique, and soon, and the organic EL element 2 is formed on an insulatingplanarization film (interlayer insulating film) 19 that covers thispixel circuit 18. The lower electrode (anode electrode, in the presentform example) 4 of the organic EL element 2 is electrically connected tothe pixel circuit 18 via a pixel contact 20. The pixel contact 20 isformed e.g. by, in the manufacturing step of the organic EL displaydevice 1, forming a connection hole that reaches the pixel circuit 18 inthe planarization film 19 and filling this connection hole with anelectrically-conductive material after forming the planarization film 19that covers the pixel circuit 18 over the element formation substrate 3.

Furthermore, an auxiliary electrode 21 is formed into a rectangularframe shape over the element formation substrate 3. The pluralsub-pixels 15 are arranged in a matrix inside the frame of thisauxiliary electrode 21, i.e. in the pixel area, and auxiliaryinterconnects 22 are formed along the horizontal and vertical directionsin the pixel area. In the example of FIG. 5 , for convenience ofdescription, total 16 sub-pixels 15 on four rows×four columns arearranged in the pixel area. In addition, the uppermost row is defined asthe first row, and the leftmost column is defined as the first column.

In each sub-pixel 15, one pixel contact 20 for the electrical connectionto the pixel circuit 18 is provided. The pixel contact 20 is formed on aprotrusion 15A arising from partial protrusion from one side of therectangular shape of the lower electrode 4, if the lower electrode 4,which defines the planar size (area) of the sub-pixel 15, is formed intothe rectangular shape in plan view. The reason why the pixel contact 20is formed on the protrusion 15A of the sub-pixel 15 in this manner is asfollows.

Specifically, when the organic EL element 2 is caused to emit lightthrough current application thereto, the desired light emission statecan not be obtained at the formation part of the pixel contact 20. Thus,in general, the formation part of the pixel contact 20 is masked so asto be a non-light-emission part. In this case, if the area of thesub-pixel 15 is so enlarged as to encompass the protrusion 15A andthereby the outer shape of this sub-pixel 15 is set to a rectangularshape for example, one part of this rectangular shape (the formationpart of pixel contact 20) becomes the non-light-emission part.Consequently, the outer shape of a light emitting pixel becomes anirregular shape arising from cutting-off of one part of the rectangularshape. In contrast, if the pixel contact 20 is formed on the protrusion15A of the sub-pixel 15 as described above, the outer shape of a lightemitting pixel is a regular rectangular shape suitable for imagedisplaying.

The auxiliary electrode 21 and the auxiliary interconnects 22 are formedon the planarization film 19 simultaneously with the lower electrode 4,in order to decrease the resistance of the upper electrode 7 (prevent avoltage drop in the upper electrode 7). Therefore, the auxiliaryelectrode 21 and the auxiliary interconnects 22 are formed at the samelayer level as that of the lower electrode 4 by using the sameelectrically-conductive material as that of the lower electrode 4. Theauxiliary interconnects 22 are formed in a continuous manner from theauxiliary electrode 21 toward the pixel area. More specifically, thevertical auxiliary interconnects 22 along the row direction are formedinto vertical straight lines between the sub-pixels 15 adjacent to eachother along the column direction at intervals of every one sub-pixel.The horizontal auxiliary interconnects 22 along the column direction areformed into horizontal straight lines between the sub-pixels 15 adjacentto each other along the row direction at intervals of every twosub-pixels.

On the other hand, each sub-pixel 15 is formed in the rectangular areadefined by the auxiliary electrode 21 and the auxiliary interconnects 22in such a manner as to be isolated from the auxiliary electrode 21 andthe auxiliary interconnects 22. Therefore, although the auxiliaryelectrode 21 and the auxiliary interconnects 22 are electricallyconnected to each other, the lower electrode 4, which is formed for eachsub-pixel 15, is electrically insulated from the auxiliary electrode 21and the auxiliary interconnects 22.

The upper electrode 7 is electrically connected to the auxiliaryelectrode 21 via plural auxiliary electrode contacts 23. Furthermore,the upper electrode 7 is electrically connected to the auxiliaryinterconnects 22 via plural auxiliary interconnect contacts 24. Therespective auxiliary electrode contacts 23 are provided in the formationarea of the auxiliary electrode 21 surrounding the pixel area. Therespective auxiliary interconnect contacts 24 are provided in theformation area (within the interconnect width) of the auxiliaryinterconnects 22 disposed in the pixel area. Therefore, the auxiliaryelectrode contacts 23 are disposed outside the pixel area, and theauxiliary interconnect contacts 24 are disposed inside the pixel area.

The auxiliary electrode contacts 23 and the auxiliary interconnectcontacts 24 are formed e.g. by, in the manufacturing step of the organicEL display device 1, forming connection holes that penetrate theinsulating layer 5 and reach the auxiliary electrode 21 and theauxiliary interconnects 22 and filling the connection holes with thematerial (electrically-conductive material) of the upper electrode 7before forming the upper electrode 7 over the element formationsubstrate 3.

As a feature of the display device according to an embodiment of thepresent invention, m (m is an integer equal to or larger than two)sub-pixels 15 adjacent to each other along the row direction and/or thecolumn direction as the arrangement directions of the sub-pixels 15 areregarded as one group, and n (n is a natural number smaller than m)auxiliary interconnect contacts 24 are formed for each group. In thefirst embodiment, two sub-pixels 15 adjacent to each other along the rowdirection are regarded as one group, and one auxiliary interconnectcontact 24 is formed for each group. Specifically, for the sub-pixels 15on the first column, the auxiliary interconnect 22 is formed between thegroup composed of the upper two sub-pixels 15 and the group composed ofthe lower two sub-pixels 15, and one auxiliary interconnect contact 24is provided on this auxiliary interconnect 22. This feature applies alsoto the sub-pixels 15 on the second, third, and fourth columns.

In FIG. 5 , four sub-pixels 15 are arranged along the row direction, andtherefore only one horizontal auxiliary interconnect 22 is formed foreach column. However, in practice, a large number of sub-pixels 15 arearranged along the row direction, and thus the number of horizontalauxiliary interconnects 22 also increases correspondingly. For example,although not shown in a drawing, when 16 sub-pixels 15 are arrangedalong the row direction on each column, the number of horizontalauxiliary interconnects 22 per one column is seven, and thus the numberof auxiliary interconnect contacts 24 per one column is also seven.

Employing such a layout eliminates the need to ensure the area forforming the auxiliary interconnect contacts 24 between the sub-pixels 15on the first row and the sub-pixels 15 on the second row, although thereis a need to ensure the area for forming the auxiliary interconnectcontacts 24 between the sub-pixels 15 on the second row and thesub-pixels 15 on the third row, for example. Thus, of the respectivesub-pixels 15 adjacent to each other along the row direction, thesub-pixels 15 on the first row and the sub-pixels 15 on the second rowcan be disposed with the intermediary of a distance therebetween smallerthan that between the sub-pixels 15 on the second row and the sub-pixels15 on the third row.

Therefore, the sub-pixels 15 can be arranged along the row directionwith higher density compared with the layout of FIG. 24 . As a result,the occupation area of the sub-pixels 15 (the lower electrodes 4) in thepixel area can be increased. Thus, enhancement in the aperture ratio ofthe pixels can be realized. The enhancement in the aperture ratio of thepixels allows suppression of the value (density) of the current thatflows through the organic EL element 2 per unit area, and thuscontributes to extension of the life of the organic EL element 2.Furthermore, if the pixel size in the first embodiment is the same asthat in the layout of FIG. 24 , a larger number of sub-pixels 15 can bedisposed in the pixel area in the first embodiment. This can realizeenhancement in the definition of displaying.

Second Embodiment

FIG. 7 is a schematic plan view showing the layout in an organic ELdisplay device according to a second embodiment of the presentinvention.

The second embodiment is the same as the first embodiment in that twosub-pixels 15 adjacent to each other along the row direction areregarded as one group and one auxiliary interconnect contact 24 isformed for each group, but is different from the first embodiment in thepositional relationship between the pixel contacts 20 provided for thesub-pixels 15 in each group. Specifically, in the first embodiment, ofthe upper and lower two sub-pixels 15 of the same group, one sub-pixel15 has the pixel contact 20 near the upper left corner thereof, and theother sub-pixel 15 has the pixel contact 20 near the lower left cornerthereof. In contrast, in the second embodiment, of the upper and lowertwo sub-pixels 15 of the same group, one sub-pixel 15 has the pixelcontact 20 near the lower left corner thereof, and the other sub-pixel15 also has the pixel contact 20 near the lower left corner thereof.

Specifically, in the first embodiment, the positions of the pixelcontacts 20 of the upper and lower two sub-pixels 15 of the same groupare inverted from each other along the row direction (verticallyinverted). In contrast, in the second embodiment, the positions of thepixel contacts 20 of the upper and lower two sub-pixels 15 of the samegroup are not inverted from each other along the row direction butaligned with each other (i.e., the pixel contacts 20 are disposed at thesame position with respect to the sub-pixel 15). Therefore, in thelayout of the second embodiment, the distance between the upper andlower two sub-pixels 15 of the same group is larger than that in thefirst embodiment.

By employing such a layout, the following advantage can be achieved inaddition to the same advantage as that by the first embodiment.Specifically, in the first embodiment, the distance between thesub-pixels 15 on the second row and the third row is larger than thatbetween the sub-pixels 15 on the first row and the second row.Therefore, the color arrangement when the sub-pixels 15 are arranged foreach of the RGB colors is as shown in FIG. 8 for example. In this case,the part involving fluctuation in the distance between the RGB pixelsalong the row direction exists continuously along the column directionacross the entire pixel area. This will deteriorate the uniformity ofthe screen.

In contrast, in the second embodiment, the distance between the upperand lower two sub-pixels 15 of the same group (e.g., the distancebetween the sub-pixels 15 on the first row and the second row) is largerthan that in the first embodiment. Thus, the difference in the pixeldistance along the row direction is smaller. Consequently, theuniformity of the screen is more favorable compared with the firstembodiment.

Third Embodiment

FIG. 9 is a schematic plan view showing the layout in an organic ELdisplay device according to a third embodiment of the present invention.

The third embodiment is the same as the first embodiment in that twosub-pixels 15 adjacent to each other along the row direction areregarded as one group and one auxiliary interconnect contact 24 isformed for each group, but is different from the first embodiment in thepositional relationship between the pixel contacts 20 provided for thesub-pixels 15 in each group. Specifically, in the first embodiment, ofthe upper and lower two sub-pixels 15 of the same group, one sub-pixel15 has the pixel contact 20 near the upper left corner thereof, and theother sub-pixel 15 has the pixel contact 20 near the lower left cornerthereof. In contrast, in the third embodiment, of the upper and lowertwo sub-pixels 15 of the same group, one sub-pixel 15 has the pixelcontact 20 near the lower left corner thereof, and the other sub-pixel15 has the pixel contact 20 near the upper left corner thereof.

Therefore, the first embodiment and the third embodiment are the same inthat the positions of the pixel contacts 20 of the upper and lower twosub-pixels 15 of the same group are inverted from each other along therow direction (vertically inverted). However, in the third embodiment,the pixel contacts 20 of the upper and lower two sub-pixels 15 of thesame group are disposed to face each other along the row direction. Thisis the difference from the first embodiment.

Therefore, in the layout of the third embodiment, the distance betweenthe upper and lower two sub-pixels 15 of the same group is larger thanthat in the first embodiment. Moreover, in the second embodiment, thearea for forming one pixel contact 20 is ensured between the upper andlower two sub-pixels 15 of the same group. In the third embodiment, thearea for forming two pixel contacts 20 is ensured between the upper andlower two sub-pixels 15 of the same group. Therefore, in the layout ofthe third embodiment, the distance between the upper and lower twosub-pixels 15 of the same group is larger also than that in the secondembodiment.

By employing such a layout, the following advantage can be achieved inaddition to the same advantage as that by the first embodiment.Specifically, in the third embodiment, the distance between the upperand lower two sub-pixels 15 of the same group (e.g., the distancebetween the sub-pixels 15 on the first row and the second row) is largerthan that in the second embodiment. Thus, the difference in the pixeldistance along the row direction is small, and therefore the sub-pixels15 can be disposed with the intermediary of an equal distance along therow direction. Consequently, the uniformity of the screen is furtherenhanced compared with the second embodiment.

Fourth Embodiment

FIG. 10 is a schematic plan view showing the layout in an organic ELdisplay device according to a fourth embodiment of the presentinvention.

The fourth embodiment is the same as the third embodiment in that twosub-pixels 15 adjacent to each other along the row direction areregarded as one group and one auxiliary interconnect contact 24 isformed for each group, in that the positions of the pixel contacts 20 ofthe upper and lower two sub-pixels 15 of the same group are invertedfrom each other along the row direction (vertically inverted), and inthat the pixel contacts 20 of the upper and lower two sub-pixels 15 ofthe same group are disposed to face each other along the row direction.However, the fourth embodiment is different from the third embodiment inthat, regarding the combining of two sub-pixels adjacent to each otheralong the row direction into one pair, the position of the combining ofthe upper and lower two sub-pixels 15 in the row direction is differentbetween the odd-numbered columns and the even-numbered columns.

Specifically, on the first column and the third column, the sub-pixels15 on the first row and the second row are paired with each other, andthe sub-pixels 15 on the third row and the fourth row are paired witheach other. In contrast, on the second column and the fourth column, thesub-pixels 15 on the second row and the third row are paired with eachother. Furthermore, although not shown in a drawing, when 16 sub-pixels15 are arranged along the row direction on each column for example, thefollowing sub-pixels 15 are paired with each other on the first columnand the third column: the sub-pixels 15 on the first and second rows;the sub-pixels 15 on the third and fourth rows; . . . ; the sub-pixels15 on the thirteenth and fourteenth rows; and the sub-pixels 15 on thefifteenth and sixteenth rows. In addition, the following sub-pixels 15are paired with each other on the second column and the fourth column:the sub-pixels 15 on the second and third rows; the sub-pixels 15 on thefourth and fifth rows; . . . ; the sub-pixels 15 on the twelfth andthirteenth rows; and the sub-pixels 15 on the fourteenth and fifteenthrows.

By employing such a layout, the following advantage can be achieved inaddition to the same advantage as that by the third embodiment.Specifically, the position of the combining of two sub-pixels adjacentto each other along the row direction on the odd-numbered columns isshifted in the row direction with respect to that on the even-numberedcolumns by the distance equivalent to one sub-pixel. Thus, the auxiliaryinterconnect contacts 24 are disposed in a staggered manner across theentire pixel area. Therefore, in the color arrangement when thesub-pixels 15 are arranged for each of the RGB colors, the partinvolving fluctuation in the distance between the RGB pixels along therow direction does not exist continuously along the column direction inthe pixel area but dispersed uniformly across the entire pixel area.Consequently, the uniformity of the screen is very favorable.

Fifth Embodiment

FIG. 11 is a schematic plan view showing the layout in an organic ELdisplay device according to a fifth embodiment of the present invention.

In the fifth embodiment, the number of sub-pixels 15 included in thesame group is different from that in the first embodiment. Specifically,in the first embodiment, two sub-pixels 15 adjacent to each other alongthe row direction are regarded as one group, and one auxiliaryinterconnect contact 24 is formed for each group. In contrast, in thefifth embodiment, four sub-pixels 15 adjacent to each other along therow direction are regarded as one group, and one auxiliary interconnectcontact 24 is formed for each group.

Of four sub-pixels 15 of the same group, the inner (center-side) twosub-pixels 15 have the pixel contacts 20 that are disposed to face eachother along the row direction. The auxiliary interconnect 22 ispartially extended between these two sub-pixels 15, and the auxiliaryinterconnect contact 24 is provided on this partially-extended auxiliaryinterconnect 22. Furthermore, although not shown in a drawing, when 16sub-pixels 15 are arranged along the row direction on each column forexample, the unit obtained by combining four sub-pixels 15 adjacent toeach other along the row direction into one group as described above isrepeatedly expanded along the row direction for four groups in such away that the horizontal auxiliary interconnects 22 each having noauxiliary interconnect contact 24 thereon are interposed between thegroups. Therefore, the horizontal auxiliary interconnects 22 do notexist between the sub-pixels 15 included in the same group but areformed only between the groups.

If such a layout is employed, it is sufficient to provide only oneauxiliary interconnect contact 24 per four sub-pixels 15 regarding therow direction. In addition, because this auxiliary interconnect contact24 is provided among the sub-pixels 15 of the same group, the sub-pixels15 can be arranged along the row direction with higher density comparedwith the first embodiment. As a result, the fifth embodiment isadvantageous in enhancing the aperture ratio of the pixels and thedefinition of displaying.

In the first to fifth embodiments, two or four sub-pixels 15 adjacent toeach other along the row direction are regarded as one group, and oneauxiliary interconnect contact 24 is formed for each group. However, theconfiguration is not limited thereto. For example, although not shown ina drawing, three or five or more sub-pixels 15 adjacent to each otheralong the row direction may be regarded as one group, and one auxiliaryinterconnect contact 24 may be formed for each group. The number ofauxiliary interconnect contacts 24 formed for each group may be any aslong as it is smaller than the number of sub-pixels 15 included in thesame group, like the case in which four sub-pixels 15 adjacent to eachother along the row direction are regarded as one group and twoauxiliary interconnect contacts 24 are formed for each group. Moreover,if four sub-pixels 15 adjacent to each other along the row direction arecombined into one group, the uniformity of the screen can be enhanced byshifting the position of the combining of the sub-pixels 15 on theodd-numbered columns in the row direction with respect to that on theeven-numbered columns similarly to the fourth embodiment.

Sixth Embodiment

FIG. 12 is a schematic plan view showing the layout in an organic ELdisplay device according to a sixth embodiment of the present invention.

In the sixth embodiment, two sub-pixels 15 adjacent to each other alongthe column direction are regarded as one group, and one auxiliaryinterconnect contact 24 is formed for each group. Specifically,regarding the sub-pixels 15 on the first row, the sub-pixels 15 on thefirst column and the second column are paired with each other, and thesub-pixels 15 on the third column and the fourth column are paired witheach other. Furthermore, one auxiliary interconnect contact 24 is formedfor each group. In addition, of the left and right two sub-pixels 15 ofthe same group, the left sub-pixel 15 has the pixel contact 20 near thelower left corner thereof, and the right sub-pixel 15 has the pixelcontact 20 near the lower right corner thereof.

The auxiliary interconnect contact 24 is formed on the verticalauxiliary interconnect 22 that runs between the left and right twosub-pixels 15 of the same group. More specifically, between the left andright two sub-pixels 15 of the same group, the interconnect width of theauxiliary interconnect 22 is partially increased at the intersection ofthe vertical and horizontal auxiliary interconnects 22, and theauxiliary interconnect contact 24 is provided on this partially-widenedpart. The auxiliary interconnect contact 24 is disposed between thepixel contacts 20 of the left and right two sub-pixels 15 of the samegroup (at an intermediate part). This feature applies also to thesub-pixels 15 on the second, third, and fourth rows.

By employing such a layout, the interconnect width of the horizontalauxiliary interconnects 22 formed between the sub-pixels 15 adjacent toeach other along the row direction can be decreased, and thus thesub-pixels 15 can be arranged along the row direction with higherdensity, compared with the layout of FIG. 24 . Thus, enhancement in theaperture ratio of the pixels and the definition of displaying can berealized similarly to the first embodiment.

Seventh Embodiment

FIG. 13 is a schematic plan view showing the layout in an organic ELdisplay device according to a seventh embodiment of the presentinvention.

In the seventh embodiment, total four sub-pixels 15 arising fromcombination of two sub-pixels 15 adjacent to each other along the rowdirection and two sub-pixels 15 adjacent to each other along the columndirection are regarded as one group, and one auxiliary interconnectcontact 24 is formed for each group. Specifically, of the sub-pixels 15on four rows×four columns, the following sub-pixels 15 are regarded asone group: four sub-pixels 15 on the first and second rows and the firstand second columns; four sub-pixels 15 on the first and second rows andthe third and fourth columns; four sub-pixels 15 on the third and fourthrows and the first and second columns; four sub-pixels 15 on the thirdand fourth rows and the third and fourth columns.

Furthermore, although not shown in a drawing, when 16 sub-pixels 15 arearranged along the row direction on each column for example, the unitobtained by combining four sub-pixels 15 adjacent to each other alongthe row and column directions into one group as described above isrepeatedly expanded along the row direction for four groups in such away that the horizontal auxiliary interconnects 22 each having theauxiliary interconnect contact 24 thereon are interposed between thegroups.

If such a layout is employed, the number of horizontal auxiliaryinterconnects 22 is smaller compared with the sixth embodiment, and thusthe sub-pixels 15 can be arranged along the row direction with higherdensity. Consequently, the seventh embodiment is advantageous inenhancing the aperture ratio of the pixels and the definition ofdisplaying.

Eighth Embodiment

FIG. 14 is a schematic plan view showing the layout in an organic ELdisplay device according to an eighth embodiment of the presentinvention.

The eighth embodiment is the same as the seventh embodiment in that foursub-pixels 15 adjacent to each other along the row and column directionsare regarded as one group and one auxiliary interconnect contact 24 isformed for each group, but is different from the seventh embodiment inthe positional relationship among the pixel contacts 20 of foursub-pixels 15 of the same group.

Specifically, in the seventh embodiment, the positions of the pixelcontacts 20 of two sub-pixels 15 adjacent to each other along the rowdirection, of four sub-pixels 15 of the same group, are inverted fromeach other along the row direction (vertically inverted). In contrast,in the eighth embodiment, the positions of the pixel contacts 20 of twosub-pixels 15 adjacent to each other along the row direction, of foursub-pixels 15 of the same group, are not inverted from each other alongthe row direction but aligned with each other at the same position(lower left or lower right).

By employing such a layout, the following advantage is achieved inaddition to the same advantage as that by the seventh embodiment.Specifically, the distance between the sub-pixels 15 along the rowdirection is equalized compared with the seventh embodiment. Thus, theuniformity of the screen is favorable.

Ninth Embodiment

FIG. 15 is a schematic plan view showing the layout in an organic ELdisplay device according to a ninth embodiment of the present invention.

The ninth embodiment is the same as the seventh embodiment in that foursub-pixels 15 adjacent to each other along the row and column directionsare regarded as one group and one auxiliary interconnect contact 24 isformed for each group, but is different from the seventh embodiment inthe positions of the pixel contacts 20 corresponding to four sub-pixels15 of the same group.

Specifically, in the seventh embodiment, the auxiliary interconnectcontact 24 is disposed between the pixel contacts 20 of the lower twosub-pixels 15 of four sub-pixels 15 of the same group. In contrast, inthe ninth embodiment, the auxiliary interconnect contact 24 is providedat the center of four sub-pixels 15 of the same group.

More specifically, in the ninth embodiment, of four sub-pixels 15 of thesame group, the upper left sub-pixel 15 has the pixel contact 20 nearthe lower left corner thereof, the upper right sub-pixel 15 has thepixel contact 20 near the lower right corner thereof, the lower leftsub-pixel 15 has the pixel contact 20 near the upper left cornerthereof, and the lower right sub-pixel 15 has the pixel contact 20 nearthe upper right corner thereof. Based on this structure, theinterconnect width of the vertical auxiliary interconnect 22 ispartially increased in the area surrounded by these four sub-pixels 15,and the auxiliary interconnect contact 24 is formed on thispartially-widened part.

By employing such a layout, the same advantage as that by the eighthembodiment can be achieved.

Tenth Embodiment

FIG. 16 is a schematic plan view showing the layout in an organic ELdisplay device according to a tenth embodiment of the present invention.

In the tenth embodiment, four sub-pixels 15 adjacent to each other alongthe column direction are regarded as one group, and two auxiliaryinterconnect contacts 24 are formed for each group. More specifically,if the horizontal four sub-pixels 15 of the same group are defined asthe first sub-pixel 15, the second sub-pixel 15, the third sub-pixel 15,and the fourth sub-pixel 15, respectively, from the left end to theright end, the first sub-pixel 15 has the pixel contact 20 near thelower left corner thereof, the second sub-pixel 15 has the pixel contact20 near the lower right corner thereof, the third sub-pixel 15 has thepixel contact 20 near the lower left corner thereof, and the fourthsub-pixel 15 has the pixel contact 20 near the lower right cornerthereof. That is, the positions of the pixel contacts 20 of thesub-pixels 15 adjacent to each other along the column direction areinverted from each other along the column direction. Thus, of thehorizontal four sub-pixels 15 of the same group, the left-side twosub-pixels 15 and the right-side two sub-pixels 15 have the positionalrelationship of horizontal symmetry.

Furthermore, although not shown in a drawing, when 16 sub-pixels 15 arearranged along the column direction on each row for example, the unitobtained by combining four sub-pixels 15 adjacent to each other alongthe column direction into one group as described above is repeatedlyexpanded along the column direction for four groups in such a way thatthe vertical auxiliary interconnects 22 each having no auxiliaryinterconnect contact 24 thereon are interposed between the groups.Therefore, the vertical auxiliary interconnects 22 do not exist betweenthe sub-pixels 15 included in the same group but are formed only betweenthe groups.

If such a layout is employed, the number of vertical auxiliaryinterconnects 22 is smaller compared with the sixth embodiment, and thusthe sub-pixels 15 can be arranged along the column direction with higherdensity. Consequently, the tenth embodiment is advantageous in enhancingthe aperture ratio of the pixels and the definition of displaying.

Eleventh Embodiment

FIG. 17 is a schematic plan view showing the layout in an organic ELdisplay device according to an eleventh embodiment of the presentinvention. FIG. 18 is a sectional view of major part of the organic ELdisplay device of the eleventh embodiment.

In the above-described first to tenth embodiments, the auxiliaryinterconnect contact 24 for electrically connecting the upper electrode7 to the auxiliary interconnect 22 at the same layer level as that ofthe lower electrode 4 is formed as shown in FIG. 6 . On the other hand,in the eleventh embodiment, an auxiliary interconnect 220 is formed atthe same layer level as that of the pixel circuit 18 on the elementformation substrate 3 as shown in FIG. 18 . Furthermore, an auxiliaryinterconnect contact 240 for electrically connecting the upper electrode7 to the auxiliary interconnect 220 is formed. It is preferable that theauxiliary interconnect 220 be formed of the same layer as, of the layersincluded in the pixel circuit 18, the electrically-conductive layerhaving the lowest resistance, such as a layer composed of an aluminummaterial. The sheet resistance of the auxiliary interconnect 220composed of aluminum is sufficiently lower than that of the upperelectrode 7 (by a factor of about one-thousandth), and thus theresistance of the upper electrode 7 can be decreased by electricallyconnecting the upper electrode 7 to the auxiliary interconnect 220.

As shown in FIG. 17 , an auxiliary electrode 210 and the auxiliaryinterconnects 220 are formed at the same layer level as that of thepixel circuit 18. Therefore, although the auxiliary electrode 210 andthe auxiliary interconnects 220 are electrically connected to eachother, the lower electrode 4, which is formed on the planarization film19 for each sub-pixel 15, is electrically insulated from the auxiliaryelectrode 210 and the auxiliary interconnects 220.

The upper electrode 7 is electrically connected to the auxiliaryelectrode 210 via plural auxiliary electrode contacts 230. Furthermore,the upper electrode 7 is electrically connected to the auxiliaryinterconnects 220 via plural auxiliary interconnect contacts 240. Therespective auxiliary electrode contacts 230 are provided in theformation area of the auxiliary electrode 210 surrounding the pixelarea. The respective auxiliary interconnect contacts 240 are provided inthe formation area (within the interconnect width) of the auxiliaryinterconnects 220 disposed in the pixel area. Thus, the auxiliaryelectrode contacts 230 are disposed outside the pixel area, and theauxiliary interconnect contacts 240 are disposed inside the pixel area.

By employing such a layout, if the pixel circuit 18 is formed in an areasmaller than the lower electrode 4 for example, the auxiliaryinterconnect 220 having a predetermined width can be formed between theadjacent pixel circuits 18 and the pitch of the sub-pixels 15 can bedecreased, compared with the first embodiment.

Application Examples

The organic EL display device 1 having the above-described configurationcan be applied to various kinds of the electronic apparatus shown inFIGS. 19 to 23 . Specifically, the organic EL display device 1 can beapplied to the electronic apparatus in any field that displays an imageor video based on a video signal input to the electronic apparatus orproduced in the electronic apparatus, such as a digital camera, laptoppersonal computer, a portable terminal apparatus typified by a cellularphone, and video camera.

FIG. 19 is a perspective view showing a television as a firstapplication example. The television according to the present applicationexample includes a video display screen 101 composed of a front panel102, a filter glass 103, and so on, and the above-described organic ELdisplay device 1 can be applied to the video display screen 101.

FIGS. 20A and 20B are diagrams showing a digital camera as a secondapplication example: FIG. 20A is a front-side perspective view and FIG.20B is a rear-side perspective view. The digital camera according to thepresent application example includes a light emitter 111 for flash, adisplay part 112, a menu switch 113, a shutter button 114, and so on,and the above-described organic EL display device 1 can be applied tothe display part 112.

FIG. 21 is a perspective view showing a laptop personal computer as athird application example. The laptop personal computer according to thepresent application example includes in a main body 121 thereof akeyboard 122 operated in inputting of characters and so forth, a displaypart 123 for displaying images, and so on. The above-described organicEL display device 1 can be applied to the display part 123.

FIG. 22 is a perspective view showing a video camera as a fourthapplication example. The video camera according to the presentapplication example includes a main body 131, a lens 132 that isdisposed on the front side of the camera and used to capture a subjectimage, a start/stop switch 133 for imaging operation, a display part134, and so on. The above-described organic EL display device 1 can beapplied to the display part 134.

FIGS. 23A to 23G are diagrams showing a cellular phone as a portableterminal apparatus as a fifth application example: FIGS. 23A and 23B area front view and side view, respectively, of the opened state, and FIGS.23C, 23D, 23E, 23F, and 23G are a front view, left-side view, right-sideview, top view, and bottom view, respectively, of the closed state. Thecellular phone according to the present application example includes anupper casing 141, a lower casing 142, a connection (hinge) 143, adisplay 144, a sub-display 145, a picture light 146, a camera 147, andso on. The above-described organic EL display device 1 can be applied tothe display 144 and the sub-display 145.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factor in so far as they arewithin the scope of the appended claims or the equivalents thereof.

What is claimed is:
 1. A display device, comprising: a plurality ofsub-pixels in a pixel region, the plurality of sub-pixels divided into aplurality of groups, each group including at least a first sub-pixel anda second sub-pixel adjacent to each other along a row direction or acolumn direction, each sub-pixel including a light emitting element; andpotential lines formed into a rectangular frame, each sub-pixel beingarranged in the rectangular frame, wherein, for each group, the firstsub-pixel has a lower electrode with a first pixel contact connected toa first pixel circuit, the second sub-pixel has a lower electrode with asecond pixel contact connected to a second pixel circuit, the firstcontact and the second contact are disposed to face each other, one ofthe potential lines is electrically connected to one of the lowerelectrodes via a first contact portion in a peripheral region.